The present invention relates to a spool structure assembled to an electromagnetic relay.
Heretofore, when disposing an electromagnetic relay, in particular an electromagnetic relay that makes and brakes an electric current having a high capacity on a printed wiring board or a mounting plate within a device, for example, the following three methods are conceived as a method of connecting coil terminals and contact terminals of the electromagnetic relay.
As the first method, a method is exemplified in which connection between coil terminals and a coil-driving circuit, and connection between contact terminals and a load such as a motor or a solenoid are provided by connecting the respective terminals to a wiring pattern on a printed circuit board.
As the second method, a method is exemplified in which the connection between coil terminals and a coil-driving circuit is provided by connecting these portions to a wiring pattern on a printed circuit board, while the connection between contact terminals and a load such as a motor or a solenoid is provided by an electric wire via tab terminal portions extended from the contact terminals.
As the third method, a method is exemplified in which the connection between coil terminals and a coil-driving circuit, and the connection between contact terminals and a load such as a motor or a solenoid are provided by an electric wire via tab terminal portions extended from the respective terminals.
However, if the connection is attempted by any one of the above methods, positions of the coil terminals and the contact terminals, which are protruded from a housing of the electromagnetic relay, are individually different from one another. Therefore, even among those electromagnetic relays having the same function and performance, the following three types of electromagnets had to be produced separately as the electromagnet to be built in.
That is, for the first method, the coil terminals and the contact terminals require being protruded from the same surface of the housing that is in contact with the printed wiring board.
Further, for the second method, the coil terminals require being protruded from a bottom surface of the housing that is in contact with the printed wiring board, while the tab terminal portions of the contact terminals require being protruded from a ceiling surface positioned on the opposite side from the bottom surface.
Furthermore, for t he third method, the tab terminal portions of the coil terminals an d the contact terminals require being protruded from a surface positioned on the opposite side from the surface on which an electromagnetic relay is mounted.
As mentioned above, if the terminals protrude in different directions, positions of twining portions of the coil terminals are individually different and therefore positions of guide grooves required at the time of coil winding are different. For this r reason , various types of spools of different shapes had to be prepared depending on the positions of the twining portions.
As one example of the spools, for example, as shown in FIG. 10, there is a spool 1 both end portions of which body 2 are formed with flanges 3, 4 that are asymmetrical shapes. The flange 3 is provided with a pair of terminal holes 5, 6 in parallel, which holes are used for press fitting coil terminals (not shown) from the lower side so as to protrude their twining portions from an upper end surface of the flange. An inward surface of the flange 3 is formed with a coil guide groove 7 to be used during the start of a coil winding process.
In particular, among high capacity-use electromagnetic relays, there is the one having a structure in which a flange 4 on one side of a spool 1 is formed with a fixed contact terminal-use holding portion (not shown). Therefore, the above spool has a complicated shape, and its mold is expensive because of this.
Accordingly, preparing various types of spools depending on different connection methods not only makes inventory control of the spools complicated but also requires various types of molds. Thus, there was a problem in that neither cost required for investment in molds nor production cost can be reduced.
An object of the present invention is to provide a spool structure for an electromagnetic relay which is easy in inventory control and low in production cost and high in production efficiency as well as productivity.
The spool structure for an electromagnetic relay according to the present invention comprises a body, and flanges respectively formed on both end portions of the body, the one side flange being provided with at least two coil terminal holes that permit coil terminals to be press fitted and also permit their twining portions to be protruded, while the other side flange being integrally formed with a fixed contact terminal-use holding part; wherein an inward surface of the one side flange is formed with at least two coil guide grooves for start-up of coil winding, which grooves are in point symmetrical with respect to the central axis of the body so that they are individually positioned between the coil terminal holes.
According to the present invention, even in the case where coil terminals of different shapes are press-fitted into coil terminal holes so as to protrude their twining portions from different directions, the coil guide grooves are so formed as to cope with any of the twining portions. Therefore, even if coil terminals require being assembled from different directions, it is possible to form different types of electromagnetic relays with one type of spool. As a result, the spool can be shared and the number of types of components to be controlled is reduced, which makes inventory control easy.
Further, it is not necessary to produce a plurality of expensive molds to form spools. This makes it possible to reduce production cost.
Furthermore, since spools of the same shape can be used even for different types of electromagnetic relays, it becomes unnecessary to change a setting of an automatic winding machine, which makes it possible to obtain an electromagnetic relay that is high in production efficiency.
Since the spools molded by one type of mold are used, variations in the dimension of components become small compared with conventional products. For this reason, adjustment work in assembling a component such as a yoke to the spool becomes unnecessary, which achieves an effect of improvement in productivity.